1. Field of the Invention
The invention concerns a method for automatic determination of imaging planes for an imaging procedure for visualization of a percutaneous intervention of an examination subject. The invention furthermore concerns a method for visualization in the percutaneous intervention, and a magnetic resonance system operable according to such a method.
2. Description of the Prior Art
Percutaneous intervention is a medical technique for minimally-invasive treatment of a patient (examined person). An increasing number of percutaneous interventions are implemented with accompaniment by imaging methods, for instance computed tomography (CT) or magnetic resonance tomography (MRT). Such imaging methods can be used for verification, warning or guidance of the percutaneous intervention. Medical fields in which percutaneous intervention is applied include aspiration biopsy, general biopsy, sclerotherapy, targeted supply of medicines, and heat ablation.
When such medical applications or additional medical applications are supported by imaging methods (for instance CT or MRT), the free-hand manual definition of the imaging planes—i.e. those planes for which the imaging method cyclically provides a visualization of the percutaneous intervention in the form of an image—represents the least complex technique. The correct and optimized alignment of the imaging planes, however, is one of the most essential requirements. It can be useful to continuously visualize the entire needle, the target point, and surrounding structures (for instance sensitive organs). For a manual alignment of the imaging planes, it can be necessary to verify the alignment of the imaging planes during the implementation of the percutaneous intervention. Verification can involve checking the alignment of the imaging planes with regard to general medical considerations, as well as a check with regard to the considerations that are specifically relevant to the technique of the underlying imaging method. For example, a medical professional can have particular requirements for the alignment of the imaging, while an MRT technician attends to other necessities. This can require a high degree of attention for the verification, and therefore make the percutaneous intervention more difficult and error-prone.
Both specialists in the imaging method (for instance MRT technicians or CT technicians) and expert medical personnel can typically participate in the implementation of a percutaneous intervention. Coordination of these parties during the procedure may be poor, or possible only to a limited extent. For example, the operating environment can limit communication and coordination due to a high noise volume. Furthermore, time pressure during the percutaneous intervention can limit a detailed coordination.
Furthermore, the manual arrangement of the imaging planes can be further hindered for special trajectories along which the needle is introduced into an examined person during the percutaneous intervention. Such special trajectories pertain to cases in which the trajectory does not run parallel or is not essentially parallel to one of the anatomical planes (thus for example the coronal, sagittal or transversal plane) of the examined person. Such imaging planes are known as “double oblique trajectories” in the technical terminology. It can be desirable to obtain a well-defined arrangement of the imaging planes relative to the anatomical planes of the examined person; but a different arrangement of the imaging planes (in particular with regard to the instrument trajectory) can enable a better overview and verification during the percutaneous intervention.
For example, it can be desirable for the suitable selection of the imaging planes to enable a verification of the arrangement of the trajectory relative to sensitive structures (organs, for instance). Such organs may be particularly well detectable in imaging planes that align on the conventional anatomical planes of the examined person.
Furthermore, it can be desirable to enable detection of a deviation of the needle used for the percutaneous intervention from the planned trajectory, by a suitable arrangement of the imaging planes.